I'm trying out the new events code with virt-manager and stumbled on some
minor bugs
- The python binding forgot to call LIBVIRT_BEGIN_ALLOW_THREADS,
LIBVIRT_END_ALLOW_THREADS, LIBVIRT_ENSURE_THREAD_STATE or
LIBVIRT_RELEASE_THREAD_STATE which meant virt-manager crashed
and burned in a heap of python interpretor state corruption [1]
- The API docs extracted assumes that enums without explicit value
assignements started from 1 instead of 0. This caused an off-by-1
error for all the VIR_DOMAIN_EVENT_* constants in the generated python
code.
I briefly toyed with fixing docs/apibuild.py enum handling but then instead
decided to just change libvirt.h to give explicit values.
With these two fixes and some hacks to virt-manager, I've got the
events triggering display state refreshes.
A couple more things I've not fixed but are on the todo list
- THe QEMU driver doesn't emit the ADDED or REMOVED events for VMs
which virt-manager requires in order to fully avoid polling.
- The VIR_EVENT_* constants aren't included in python, because the
API docs can't cope with enum value asignments looking like
(1 << 0) (ie fails to parse the left-shifts)
Regards,
Daniel
[1] FYI, i'm using the libvirt-glib python binding in virt-manager
http://libvirt.org/hg/libvirt-glib/ which is slightly bad too
by not doing glib thread locking calls, but we're lucky because
libvirt.so doesn't invoke any glib calls itself from the event
callback context.
Index: python/libvir.c
===================================================================
RCS file: /data/cvs/libvirt/python/libvir.c,v
retrieving revision 1.43
diff -u -p -r1.43 libvir.c
--- python/libvir.c 31 Oct 2008 10:13:45 -0000 1.43
+++ python/libvir.c 4 Nov 2008 19:45:42 -0000
@@ -1537,29 +1537,33 @@ libvirt_virConnectDomainEventCallback(vi
PyObject *pyobj_ret;
PyObject *pyobj_conn_inst = (PyObject*)opaque;
- PyObject *pyobj_dom = libvirt_virDomainPtrWrap(dom);
+ PyObject *pyobj_dom;
PyObject *pyobj_dom_args;
PyObject *pyobj_dom_inst;
PyObject *dom_class;
+ int ret = -1;
+
+ LIBVIRT_ENSURE_THREAD_STATE;
/* Create a python instance of this virDomainPtr */
+ pyobj_dom = libvirt_virDomainPtrWrap(dom);
pyobj_dom_args = PyTuple_New(2);
if(PyTuple_SetItem(pyobj_dom_args, 0, pyobj_conn_inst)!=0) {
printf("%s error creating tuple",__FUNCTION__);
- return -1;
+ goto cleanup;
}
if(PyTuple_SetItem(pyobj_dom_args, 1, pyobj_dom)!=0) {
printf("%s error creating tuple",__FUNCTION__);
- return -1;
+ goto cleanup;
}
Py_INCREF(pyobj_conn_inst);
dom_class = getLibvirtDomainClassObject();
if(!PyClass_Check(dom_class)) {
printf("%s dom_class is not a class!\n", __FUNCTION__);
- return -1;
+ goto cleanup;
}
pyobj_dom_inst = PyInstance_New(dom_class,
@@ -1571,7 +1575,7 @@ libvirt_virConnectDomainEventCallback(vi
if(!pyobj_dom_inst) {
printf("%s Error creating a python instance of virDomain\n", __FUNCTION__);
PyErr_Print();
- return -1;
+ goto cleanup;
}
/* Call the Callback Dispatcher */
@@ -1586,12 +1590,15 @@ libvirt_virConnectDomainEventCallback(vi
if(!pyobj_ret) {
printf("%s - ret:%p\n", __FUNCTION__, pyobj_ret);
PyErr_Print();
- return -1;
} else {
Py_DECREF(pyobj_ret);
- return 0;
+ ret = 0;
}
+
+cleanup:
+ LIBVIRT_RELEASE_THREAD_STATE;
+ return -1;
}
static PyObject *
@@ -1620,10 +1627,14 @@ libvirt_virConnectDomainEventRegister(AT
Py_INCREF(pyobj_conn_inst);
+ LIBVIRT_BEGIN_ALLOW_THREADS;
+
ret = virConnectDomainEventRegister(conn,
libvirt_virConnectDomainEventCallback,
(void *)pyobj_conn_inst);
+ LIBVIRT_END_ALLOW_THREADS;
+
py_retval = libvirt_intWrap(ret);
return (py_retval);
}
@@ -1650,8 +1661,12 @@ libvirt_virConnectDomainEventDeregister(
conn = (virConnectPtr) PyvirConnect_Get(pyobj_conn);
+ LIBVIRT_BEGIN_ALLOW_THREADS;
+
ret = virConnectDomainEventDeregister(conn, libvirt_virConnectDomainEventCallback);
+ LIBVIRT_END_ALLOW_THREADS;
+
Py_DECREF(pyobj_conn_inst);
py_retval = libvirt_intWrap(ret);
return (py_retval);
@@ -1679,13 +1694,15 @@ libvirt_virEventAddHandleFunc (int fd A
PyObject *cb_args;
PyObject *pyobj_args;
+ LIBVIRT_ENSURE_THREAD_STATE;
+
/* Lookup the python callback */
python_cb = PyDict_GetItemString(getLibvirtDictObject(),
"eventInvokeHandleCallback");
if(!python_cb) {
printf("%s Error finding eventInvokeHandleCallback\n", __FUNCTION__);
PyErr_Print();
- return -1;
+ goto cleanup;
}
Py_INCREF(python_cb);
@@ -1708,6 +1725,10 @@ libvirt_virEventAddHandleFunc (int fd A
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+cleanup:
+ LIBVIRT_RELEASE_THREAD_STATE;
+
return 0;
}
@@ -1715,7 +1736,11 @@ static void
libvirt_virEventUpdateHandleFunc(int fd, int event)
{
PyObject *result = NULL;
- PyObject *pyobj_args = PyTuple_New(2);
+ PyObject *pyobj_args;
+
+ LIBVIRT_ENSURE_THREAD_STATE;
+
+ pyobj_args = PyTuple_New(2);
PyTuple_SetItem(pyobj_args, 0, libvirt_intWrap(fd));
PyTuple_SetItem(pyobj_args, 1, libvirt_intWrap(event));
@@ -1724,13 +1749,20 @@ libvirt_virEventUpdateHandleFunc(int fd,
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+ LIBVIRT_RELEASE_THREAD_STATE;
}
+
static int
libvirt_virEventRemoveHandleFunc(int fd)
{
PyObject *result = NULL;
- PyObject *pyobj_args = PyTuple_New(1);
+ PyObject *pyobj_args;
+
+ LIBVIRT_ENSURE_THREAD_STATE;
+
+ pyobj_args = PyTuple_New(1);
PyTuple_SetItem(pyobj_args, 0, libvirt_intWrap(fd));
if(removeHandleObj && PyCallable_Check(removeHandleObj))
@@ -1738,6 +1770,9 @@ libvirt_virEventRemoveHandleFunc(int fd)
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+ LIBVIRT_RELEASE_THREAD_STATE;
+
return 0;
}
@@ -1754,13 +1789,15 @@ libvirt_virEventAddTimeoutFunc(int timeo
PyObject *cb_args;
PyObject *pyobj_args;
+ LIBVIRT_ENSURE_THREAD_STATE;
+
/* Lookup the python callback */
python_cb = PyDict_GetItemString(getLibvirtDictObject(),
"eventInvokeTimeoutCallback");
if(!python_cb) {
printf("%s Error finding eventInvokeTimeoutCallback\n", __FUNCTION__);
PyErr_Print();
- return -1;
+ goto cleanup;
}
Py_INCREF(python_cb);
@@ -1783,6 +1820,9 @@ libvirt_virEventAddTimeoutFunc(int timeo
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+cleanup:
+ LIBVIRT_RELEASE_THREAD_STATE;
return 0;
}
@@ -1790,7 +1830,11 @@ static void
libvirt_virEventUpdateTimeoutFunc(int timer, int timeout)
{
PyObject *result = NULL;
- PyObject *pyobj_args = PyTuple_New(2);
+ PyObject *pyobj_args;
+
+ LIBVIRT_ENSURE_THREAD_STATE;
+
+ pyobj_args = PyTuple_New(2);
PyTuple_SetItem(pyobj_args, 0, libvirt_intWrap(timer));
PyTuple_SetItem(pyobj_args, 1, libvirt_intWrap(timeout));
@@ -1799,13 +1843,19 @@ libvirt_virEventUpdateTimeoutFunc(int ti
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+ LIBVIRT_RELEASE_THREAD_STATE;
}
static int
libvirt_virEventRemoveTimeoutFunc(int timer)
{
PyObject *result = NULL;
- PyObject *pyobj_args = PyTuple_New(1);
+ PyObject *pyobj_args;
+
+ LIBVIRT_ENSURE_THREAD_STATE;
+
+ pyobj_args = PyTuple_New(1);
PyTuple_SetItem(pyobj_args, 0, libvirt_intWrap(timer));
if(updateTimeoutObj && PyCallable_Check(updateTimeoutObj))
@@ -1813,6 +1863,9 @@ libvirt_virEventRemoveTimeoutFunc(int ti
Py_XDECREF(result);
Py_DECREF(pyobj_args);
+
+ LIBVIRT_RELEASE_THREAD_STATE;
+
return 0;
}
@@ -1845,6 +1898,8 @@ libvirt_virEventRegisterImpl(ATTRIBUTE_U
Py_INCREF(updateTimeoutObj);
Py_INCREF(removeTimeoutObj);
+ LIBVIRT_BEGIN_ALLOW_THREADS;
+
virEventRegisterImpl(libvirt_virEventAddHandleFunc,
libvirt_virEventUpdateHandleFunc,
libvirt_virEventRemoveHandleFunc,
@@ -1852,6 +1907,8 @@ libvirt_virEventRegisterImpl(ATTRIBUTE_U
libvirt_virEventUpdateTimeoutFunc,
libvirt_virEventRemoveTimeoutFunc);
+ LIBVIRT_END_ALLOW_THREADS;
+
return VIR_PY_INT_SUCCESS;
}
Index: include/libvirt/libvirt.h.in
===================================================================
RCS file: /data/cvs/libvirt/include/libvirt/libvirt.h.in,v
retrieving revision 1.57
diff -u -p -r1.57 libvirt.h.in
--- include/libvirt/libvirt.h.in 24 Oct 2008 12:05:39 -0000 1.57
+++ include/libvirt/libvirt.h.in 4 Nov 2008 19:45:42 -0000
@@ -1004,14 +1004,14 @@ virDomainPtr virDomainCreateL
* a virDomainEventType is emitted during domain lifecycle events
*/
typedef enum {
- VIR_DOMAIN_EVENT_ADDED,
- VIR_DOMAIN_EVENT_REMOVED,
- VIR_DOMAIN_EVENT_STARTED,
- VIR_DOMAIN_EVENT_SUSPENDED,
- VIR_DOMAIN_EVENT_RESUMED,
- VIR_DOMAIN_EVENT_STOPPED,
- VIR_DOMAIN_EVENT_SAVED,
- VIR_DOMAIN_EVENT_RESTORED,
+ VIR_DOMAIN_EVENT_ADDED = 0,
+ VIR_DOMAIN_EVENT_REMOVED = 1,
+ VIR_DOMAIN_EVENT_STARTED = 2,
+ VIR_DOMAIN_EVENT_SUSPENDED = 3,
+ VIR_DOMAIN_EVENT_RESUMED = 4,
+ VIR_DOMAIN_EVENT_STOPPED = 5,
+ VIR_DOMAIN_EVENT_SAVED = 6,
+ VIR_DOMAIN_EVENT_RESTORED = 7,
} virDomainEventType;
/**
--
|: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :|
|: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :|
|: http://autobuild.org -o- http://search.cpan.org/~danberr/ :|
|: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|
--
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